Dead or "undead"? The curious and untidy history of Volta's concept of "contact potential".

Much of the long controversy concerning the workings of electric batteries revolved around the concept of the contact potential (especially between different types of metals), originated by Alessandro Volta in the late eighteenth century. Although Volta's original theory of batteries has been thoroughly rejected and most discussions in today's electrochemistry hardly ever mention the contact potential, the concept has made repeated comebacks through the years, and has by no means completely disappeared. In this paper, I describe four salient foci of its revivals: dry piles, thermocouples, quadrant electrometers, and vacuum phenomena.

What History Tells Us about the Distinct Nature of Chemistry.

Attention to the history of chemistry can help us recognise the characteristics of chemistry that have helped to maintain it as a separate scientific discipline with a unique identity. Three such features are highlighted in this paper. First, chemistry has maintained a distinct type of theoretical thinking, independent from that of physics even in the era of quantum chemistry.

Acidity: Modes of characterization and quantification.

This paper provides an account of early historical developments in the characterization and quantification of acidity, which may be considered preliminary steps leading to the measurement of acidity. In this "pre-history" of acidity measurement, emphasis is laid on the relative independence of the rich empirical knowledge about acids from theories of acidity. Many attempts were made to compare and assess the strengths of various acids, based on concrete laboratory operations.

The making of measurement: Editors' introduction.

This special issue consists of selected papers arising from the interdisciplinary conference "The Making of Measurement" held at the University of Cambridge on 23-24 July 2015. In this introduction, we seek ways to further productive interactions among historical, philosophical, and sociological approaches to the study of measurement without attempting to lay out a prescriptive program for a field of "measurement studies." We ask where science studies has led us, and answer: from the function to the making of measurement.

Who cares about the history of science?

The history of science has many functions. Historians should consider how their work contributes to various functions, going beyond a simple desire to understand the past correctly. There are both internal and external functions of the history of science in relation to science itself; I focus here on the internal, as they tend to be neglected these days.

Pluralism versus Periodization.

There is much potential in Frans van Lunteren’s schema of using certain important machines as focal points for characterizing large-scale trends in scientific development. However, there are difficulties with the periodization of history he proposes, particularly with regard to the periods focused around the balance and the steam engine; these machines were highly influential somewhat simultaneously, and their cultural resonances were not entirely distinct from each other. Van Lunteren rightly recognizes the multifacetedness of the epistemic, social, and material roles played by each machine.

The Chemical Revolution revisited.

I respond to the critical comments by Martin Kusch and Ursula Klein on my account of the Chemical Revolution. I comment along three different lines: descriptive, explanatory, and normative. (1) I agree with Klein that Lavoisier did not introduce drastic changes in chemical ontology, but maintain that there was methodological incommensurability in the Chemical Revolution; in response to Kusch's view, I maintain that Lavoisier's victory was slow and incomplete.

The myth of the boiling point.

Around 1800, many reputable scientists reported significant variations in the temperature of pure water boiling under normal atmospheric pressure. The reported variations included a difference of over 1 degree C between boiling in metallic and glass vessels (Gay-Lussac), and "superheating" up to 112 degrees C on extracting dissolved air out of water (De Luc). I have confirmed most of these observations in my own experiments, many of which are described in this paper.

When water does not boil at the boiling point.

Every schoolchild learns that, under standard pressure, pure water always boils at 100 degrees C. Except that it does not. By the late 18th century, pioneering scientists had already discovered great variations in the boiling temperature of water under fixed pressure.